POV-Ray : Newsgroups : povray.beta-test : Problems with scenes\lights\glassthing.pov (beta3) Server Time: 8 Mar 2021 13:30:23 GMT
  Problems with scenes\lights\glassthing.pov (beta3) (Message 1 to 2 of 2)  
From: Warp
Subject: Problems with scenes\lights\glassthing.pov (beta3)
Date: 2 May 2005 21:45:17
Message: <42769f6d@news.povray.org>
When I try to render scenes\lights\glassthing.pov, a black image
results.

  If I comment out the photons block then it renders something much
more resembling the result of pov3.6, but it's still problematic.

  Firstly, the shadow is completely black with 3.7beta3 even though
it's much lighter with 3.6.

  Secondly, the rendertime is obnoxiously longer. While pov3.6 renders
the image (at 512x256 without antialiasing) in about 3 seconds,
pov3.7beta3-sse2 renders it in 4 minutes 13 seconds. The rendering
gets stuck at a couple of places.

  Curiously, when it is stuck in those places it is very hard to
make povray stop. It will continue rendering for a quite long time
before it stops.

-- 
                                                          - Warp


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From: Chris Cason
Subject: Re: Problems with scenes\lights\glassthing.pov (beta3)
Date: 4 May 2005 19:17:23
Message: <42791fc3@news.povray.org>
Warp wrote:
>   If I comment out the photons block then it renders something much
> more resembling the result of pov3.6, but it's still problematic.
> 
>   Firstly, the shadow is completely black with 3.7beta3 even though
> it's much lighter with 3.6.

Fixed, thanks.

>   Secondly, the rendertime is obnoxiously longer. While pov3.6 renders
> the image (at 512x256 without antialiasing) in about 3 seconds,
> pov3.7beta3-sse2 renders it in 4 minutes 13 seconds. The rendering
> gets stuck at a couple of places.

Fixed, thanks. This was a major problem which has been bothering me for ages;
I finally tracked it down to the fact that the ComputeTextureColour() was
ignoring the absense of a multi-texture flag and potentially performing a
full-depth (up to max_trace_level) trace for each texture it found. In the
case of the blobs in glassthing.pov the sub-components of the blob caused
these extra rays to be cast. It would have affected CSG and meshes too.

I'll probably release a beta.4 soon with this fix.

-- Chris


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